Conventional image forming devices such as copiers or printers are generally provided with a paper path extending in a vertical direction at the vicinity of the side face of the main body of the device for downsizing the overall system. The paper path extending in a vertical direction is provided with a pair of conveying rollers for conveying a sheet of paper. It is common to install a conveying unit having one roller of the pair of conveying rollers, a transfer roller which is pressed by an image carrier to be brought into contact with the image carrier to form a transfer nip part, and the like, and to design a structure capable of opening and closing the conveying unit in relation to the main body of the device for easy clearance of paper jams and maintenance of the device in a condition where a wide range of the paper path is exposed.
For example, the patent document 1 discloses a paper conveying device having at least two parallel paper paths where a paper jam occurred therein can be cleared from only one direction. This paper conveying device includes at least two swing guide plates for opening the at least two paper paths, an opening/closing mechanism for opening or closing the swing guide plates, and an exterior cover for opening and closing the main body of the device. The swing guide plates are configured to be opened or closed with the movement of an opening or closing action of the exterior cover.
The patent document 2 discloses a constitution, in which a transfer roller is provided with a bearing member that rotatably supports a rotation axis, a spring member that presses the bearing member to the side of a photoreceptor drum, and a bearing holder that houses the bearing member and supports the bearing member so that the bearing member is movable in the housing. In this constitution, when a cover member, which is provided with the transfer roller, is closed in relation to the main body of the device, a bearing member freely moves in the housing of the bearing holder on the side of the main body of the device, and the rotation axis of the transfer roller is fitted into a guiding groove of the bearing guide of the main body of the device so that the rotation axis is opposed to the guiding groove. Thus, the transfer roller is pressed against the photoreceptor drum so that the transfer roller is brought into contact with the photoreceptor, and thereby a nip part that enables nipped transfer of a recording medium is formed.